15 research outputs found
Spatially resolved dust properties and quasar-galaxy decomposition of HyLIRG at redshift 4.4
We report spatially resolved dust properties of the quasar host galaxy BRI
1335-0417 at redshift constrained by the ALMA observations. The dust
temperature map, derived from a greybody fit to rest-frame 90 and 161 m
continuum images, shows a steep increase towards the centre, reaching K. Image decomposition analysis reveals the presence of a point source in
both dust continuum images at the same position as the highest temperature peak
and the optical quasar position, which we attribute to warm dust heated by an
active galactic nucleus (AGN). We show that a model including this warm
component along with cooler dust heated by star formation describes the global
SED better than a single component model, with dust temperatures of
87.1 K (warm component) and 52.6 K (cold
component). The star formation rate (SFR) estimated from the cold dust
component is yr, a factor of three smaller
than previous estimates due to a large AGN contribution (%).
The unresolved warm dust component also explains the steep temperature
gradient, as the temperature profile derived after the point source subtraction
is flat. We further show that AGN-host galaxy decomposition is critical for
estimating SFR distribution, as point source subtraction reduces the estimated
central SFR surface density by over a factor of three.
With this correction, spatially resolved measurements of
and the surface gas mass density
form a roughly linear sequence in the Kennicutt-Schmidt
diagram with a constant gas depletion time of 50-200 Myr.Comment: 25pages, 25figures, 4tables, Submitted to MNRAS, Comments are warmly
welcome
Detecting a disk bending wave in a barred-spiral galaxy at redshift 4.4
The recent discovery of barred spiral galaxies in the early universe ()
poses questions of how these structures form and how they influence galaxy
properties in the early universe. In this study, we investigate the morphology
and kinematics of the far infrared (FIR) continuum and [CII] emission in
BRI1335-0417 at from ALMA observations. The variations in
position angle and ellipticity of the isophotes show the characteristic
signature of a barred galaxy. The bar, kpc long in radius
and bridging the previously identified two-armed spiral, is evident in both
[CII] and FIR images, driving the galaxy's rapid evolution by channelling gas
towards the nucleus. Fourier analysis of the [CII] velocity field reveals an
unambiguous mode with a line-of-sight velocity amplitude of up to
km s; the plausible explanation is the disk's vertical
bending mode triggered by external perturbation, which presumably induced the
high star formation rate and the bar/spiral structure. The bar identified in
[CII] and FIR images of the gas-rich disk galaxy (\% of the total
mass within radius disk scale lengths) suggests a new
perspective of early bar formation -- a gravitationally unstable gas-rich disk
creating a star-forming gaseous bar, rather than a stellar bar emerging from a
pre-existing stellar disk.Comment: Submitted to MNRAS. We welcome comments
The MAGPI Survey: Effects of Spiral Arms on Different Tracers of the Interstellar Medium and Stellar Populations at z~0.3
Spiral structures are important drivers of the secular evolution of disc
galaxies, however, the origin of spiral arms and their effects on the
development of galaxies remain mysterious. In this work, we present two
three-armed spiral galaxies at z~0.3 in the Middle Age Galaxy Properties with
Integral Field Spectroscopy (MAGPI) survey. Taking advantage of the high
spatial resolution (~0.6'') of the Multi-Unit Spectroscopic Unit (MUSE), we
investigate the two-dimensional distributions of different spectral parameters:
Halpha, gas-phase metallicity, and D4000. We notice significant offsets in
Halpha (~0.2 dex) as well as gas-phase metallicities (~0.05 dex) among the
spiral arms, downstream and upstream of MAGPI1202197197 (SG1202). This
observational signature suggests the spiral structure in SG1202 is consistent
with arising from density wave theory. No azimuthal variation in Halpha or
gas-phase metallicities is observed in MAGPI1204198199 (SG1204), which can be
attributed to the tighter spiral arms in SG1204 than SG1202, coming with
stronger mixing effects in the disc. The absence of azimuthal D4000 variation
in both galaxies suggests the stars at different ages are well-mixed between
the spiral arms and distributed around the disc regions. The different
azimuthal distributions in Halpha and D4000 highlight the importance of time
scales traced by various spectral parameters when studying 2D distributions in
spiral galaxies. This work demonstrates the feasibility of constraining spiral
structures by tracing interstellar medium (ISM) and stellar population at
z~0.3, with a plan to expand the study to the full MAGPI survey.Comment: 15 pages, 11 figures, 2 tables, accepted for publication in MNRA
Improved Dynamical Constraints on the Masses of the Central Black Holes in Nearby Low-mass Early-type Galactic Nuclei And the First Black Hole Determination for NGC 205
We improve the dynamical black hole (BH) mass estimates in three nearby
low-mass early-type galaxies--NGC 205, NGC 5102, and NGC 5206. We use new
\hst/STIS spectroscopy to fit the star formation histories of the nuclei in
these galaxies, and use these measurements to create local color--mass-to-light
ratio (\ml) relations. We then create new mass models from \hst~imaging and
combined with adaptive optics kinematics, we use Jeans dynamical models to
constrain their BH masses. The masses of the central BHs in NGC 5102 and NGC
5206 are both below one million solar masses and are consistent with our
previous estimates, \Msun~and
\Msun~(3 errors), respectively.
However, for NGC 205, the improved models suggest the presence of a BH for the
first time, with a best-fit mass of
\Msun~(3 errors). This is the least
massive central BH mass in a galaxy detected using any method. We discuss the
possible systematic errors of this measurement in detail. Using this BH mass,
the existing upper limits of both X-ray, and radio emissions in the nucleus of
NGC 205 suggest an accretion rate of the Eddington rate. We
also discuss the color--\mleff~relations in our nuclei and find that the slopes
of these vary significantly between nuclei. Nuclei with significant young
stellar populations have steeper color--\mleff~relations than some previously
published galaxy color--\mleff~relations.Comment: 31 pages, 19 figures, 6 tables, Accepted to Ap
The MBHBM Project-I: measurement of the central black hole mass in spiral galaxy NGC 3504 using molecular gas kinematics
We present a dynamical mass measurement of the supermassive black hole (SMBH) in the nearby double-barred spiral galaxy NGC 3504 as part of the Measuring Black Holes in below Milky Way (M sstarf) Mass Galaxies Project. Our analysis is based on Atacama Large Millimeter/submillimeter Array cycle 5 observations of the emission line. These observations probe NGC 3504's circumnuclear gas disk (CND). Our dynamical model of the CND simultaneously constrains a black hole (BH) mass of M ⊙, which is consistent with the empirical BH–galaxy scaling relations and a mass-to-light ratio in the H band of 0.44 ± 0.12 (M ⊙/). This measurement also relies on our new estimation of the distance to the galaxy of 32.4 ± 2.1 Mpc using the surface brightness fluctuation method, which is much further than the existing distance estimates. Additionally, our observations detect a central deficit in the integrated intensity map with a diameter of 6.3 pc at the putative position of the SMBH. However, we find that a dense gas tracer CS(5 − 4) peaks at the galaxy center, filling in the 12CO(2 − 1)-attenuated hole. Holes like this one are observed in other galaxies, and our observations suggest these may be caused by changing excitation conditions rather than a true absence of molecular gas around the nucleus
Galactic dynamics and DM profile of NGC1380 with ALMA and VLT/MUSE
In order to understand the interaction between dark matter and baryonic matter in the galaxy evolution history, it is fundamental to constrain dark matter (DM) distribution in galaxies. However, it is difficult to constrain DM profile in the central region of early type galaxy because of the lack of extended neutral hydrogen gas and the degeneracy between dynamical stellar M/L and DM profile. To resolve this difficulty, we conducted combined analysis of ALMA cold molecular gas kinematics and MUSE stellar kinematics of early type fast rotator galaxy NGC1380. In addition, we used HST image to trace the stellar luminosity distribution. With the help of high resolution of ALMA image and large field of view of MUSE, we derived the central BH mass, stellar bulge, disk and DM profile
Bile acid profiles in adult patients with biliary atresia who achieve native liver survival after portoenterostomy
Abstract Bile acids have received increasing attention as a marker of the long-term prognosis and a potential therapeutic target in patients with biliary atresia, which is a progressive disease of the hepatobiliary system. A detailed analysis of serum and urinary bile acid compositions was conducted to assess the characteristics of bile acid profiles and the correlation between bile acid profiles and liver fibrosis markers in adult patients with biliary atresia who achieved bilirubin normalization. Serum total bile acids and glucuronide-conjugated (glyco- and tauro-) cholic acids (GCA and TCA) and chenodeoxycholic acids (GCDCA and TCDCA) were significantly higher in patients with biliary atresia than in healthy controls, whereas unconjugated CA and CDCA showed no significant difference. There were no significant differences in CA to CDCA ratios and glycine-to-taurine-conjugated ratios. Urinary glycocholic acid 3-sulfate (GCA-3S) was significantly higher in patients with biliary atresia. Serum GCDCA showed a strong positive correlation with Mac-2 binding protein glycosylation isomer (M2BPGi). These results demonstrate that bile acid congestion persists into adulthood in patients with biliary atresia, even after cholestasis has completely improved after Kasai portoenterostomy. These fundamental data on bile acid profiles also suggest the potential value of investigating bile acid profiles in patients with biliary atresia